viscosity function, Φ

A coefficient connecting the intrinsic viscosity, the radius of gyration and the molar mass of a chain macromolecule, according to the equation:

$[ η ] = Φ 6 3 2 ( < s 2 > ) 3 2 M$

where $[ η ]$ is the intrinsic viscosity, $s$ is the radius of gyration and $M$ is the molar mass. The viscosity function is often referred to as the Flory constant.

Source:

Purple Book, p. 64